1. Field of the Invention
The present invention relates to a camera, and more particularly, to a sequence of controlling a predetermined action of a camera, which sequence has been executed for performing photography and in which an abnormality has occurred.
2. Description of the Related Art
Cameras for performing photography generally use system described below to judge whether a shutter unit acts normally during photography.
Namely, sectors constituting part of the shutter unit have a slit formed at a predetermined position thereof. A photo-interrupter for detecting the slit is included. When a detection signal is output from the photo-interrupter, it is judged that the shutter unit acts normally.
When an output from the photo-interrupter is not detected, it is judged that the shutter unit has an abnormality. If an abnormality is thus detected, control is given so that a camera will be disabled from operating for fear the same event may be repeated, and thus placed in a non-operable state.
In a camera disclosed in Japanese Patent Publication No. 2669850, as long as an abnormality in an action is detected once, the camera is not placed in the non-operable state. After an abnormality in a predetermined action is detected a plurality of times, the camera is disabled from operating. As long as an abnormal action is detected only once, the camera remains usable thereafter. This helps a user to become conscious of the abnormal action of the camera thereafter and contributes to improvement in the user""s maneuverability.
However, the means disclosed in the Japanese Patent Publication No. 2669850 does not disable the camera from operating as long as an abnormality in the action of the shutter unit is detected only once. Even if the camera malfunctions, the same sequence is executed again. The camera would operate as if it were normal until the abnormality is detected a plurality of times. Other different defects may occur until the camera is placed in the non-operable state because the abnormality in the action has been detected a plurality of times.
The above will be described by considering a practical example. That is to say, assume that when a shutter unit fails, an abnormality is detected for the first time. At this time, the camera can still execute operations for the next photography.
Normally, prior to photography, a user often actuates a release without loading a predetermined film cartridge (not shown) in a camera body to thus carry out so-called test imaging (blind exposure).
If the camera is of a type in which even when an abnormality is detected once, the camera is not disabled from operating immediately, the user will not become aware of the fact that the camera malfunctions and therefore operates abnormally. The user may therefore load a film cartridge in preparations for actual photography.
In this case, since the camera is actually abnormal (malfunctions), an abnormality is detected for the second time during photography of the first frame. The camera is then placed in the non-operable state for the first time.
According to the system disclosed in the Japanese Patent Publication No. 2669850, discovery of an abnormality in an action of a camera is likely to be delayed. This poses a problem.
If this kind of event occurs, the user not only wastes film, but also loses a chance of exposure. Besides, the user who thought that the camera acted normally at the time of test imaging (blind exposure) will be disappointed because the camera has malfunctioned in reality. The user will distrust the camera from that time. This will affect the user""s photographic activity using the camera.
An object of the present invention is to provide a camera in which when an abnormality is detected in a photographing operation, an appropriate checking operation is executed automatically. It is then judged whether the detected abnormality in the operation is attributable to the malfunction of the camera. A user can therefore accurately recognize the state of the camera.
Briefly, according to the first aspect of the present invention, a camera capable of detecting an abnormality has photographing operation section, an abnormality detecting section, and a checking operation section. The photographing operation section causes a plurality of mechanisms included in the camera to act sequentially. The abnormality detecting section detects an abnormality in an action of a certain one of the plurality of mechanisms. Responsive to detection of an abnormality in the action of the certain mechanism achieved by the abnormality detecting section, the checking operation section causes the certain mechanism alone to act again for checking under conditions different from those under which the certain mechanism has acted to have the abnormality detected by the abnormality detecting section.
According to the second aspect of the present invention, a camera capable of detecting an abnormality has a photographing section, an abnormality detecting means, a checking operation section, an abnormality judging section, and a photography disabling section. The photographing section executes a series of photographing operations (a photographing sequence). The abnormality detecting section detects an abnormal member during the photographing sequence. Responsive to detection of an abnormal action of said abnormal member, which is involved in any operation belonging to the photographing sequence, achieved by the abnormality detecting section, the checking operation section executes a checking operation for the abnormal member under conditions different from those under which the operation belonging to the photographic sequence is executed. The abnormality judging section judges from the results of the checking operation executed by the checking operation section whether the abnormal member detected by the abnormality detecting section is still abnormal. When the abnormality judging section judges from the results of the judgment made by the abnormality judging section that the abnormal member is still abnormal, the photography disabling section disables the photographic operations of the camera.
According to the third aspect of the present invention, a camera capable of detecting an abnormality in an action involved in a photographing operation has an abnormality detecting section, a checking operation section, and an abnormality persistence judging section. The abnormality detecting section detects an abnormality in at least one of a plurality of actions involved in a series of photographing operations (a photographing sequence) initiated with a manipulation performed for initiating the photographing operations. Responsive to detection of an abnormality in the certain action achieved by the abnormality detecting section, the checking operation section forcibly executes a photographing operation involving the action, in which an abnormality is detected, according to predetermined contents immediately after the detection of the abnormality. The abnormality persistence judging section judges from the results of the operation executed by the checking operation section according to the predetermined contents whether the abnormality in the action persists.
These and other objects of the present invention and the advantages thereof will be apparent from the description below.
According to the present invention, there is provided a camera in which if an abnormality is detected in a photographic operation, an appropriate checking operation is executed automatically. It is reliably judged whether the detected abnormality in the operation is attributed to the malfunction of the camera. A user can therefore accurately recognize the state of the camera.